Two forms of substance use disorder, alcohol and cocaine, have been associated with panic disorder, a syndrome characterized by attacks of anxiety and autonomic arousal. Panic may be initiated by a number of precipitants, including the ingestion of certain abusable substances. Alternatively, drug use may follow panic in the form of self-medication. This project was initiated when one of us (HDA) discovered an abnormality in brain electrical activity in the temporal lobes of drug abusers with panic when studied by the technique of quantitative EEG with mapping (qEEG). A pilot project of fifty subjects divided into three groups- - panic disorder (PD), drug abuse (DA), and panic subjects with drug abuse (PD+DA)- further showed that panic subjects had abnormal qEEGs in the non-dominant temporal region, whereas PD+DA subjects had abnormalities in both temporal regions. The drug most commonly abused in the PD+DA group was cocaine. A second pilot was done in which structured life histories of anxiety and drug disorder symptoms were obtained in cocaine and alcohol abusers, showing in the former the onset of panic followed. cocaine use, but preceded alcoholism. If correct, these findings have relevance to the putative etiologies of some forms of panic disorder and substance abuse. The description of a cocaine mediated subtype of panic disorder whose illness may be acquired in association with the abuse of cocaine. Alternatively, other patients may suffer primary panic, and use drugs such as alcohol to self-medicate. Accordingly, the proposed study seeks 1) to replicate the pilot data, 2) prospectively test if there are electrophysiological markers which can be used to discriminate panic disorder among alcohol and cocaine abusers from pure panic subjects and from normality; and 3) test if markers predict relapse in alcohol and cocaine abuse.